* {
  margin: 0;
  padding: 0;
}

.container {
  width: 200px;
  height: 360px;
  background-color: black;
  position: relative;
}

.blockItem {
  position: absolute;
  box-sizing: border-box;
  width: 20px;
  height: 20px;
  background-color: aquamarine;
  border: solid .3px #ff0;
  top: 20px;
  left: 20px;
}

.fixedBottom {
  position: absolute;
  box-sizing: border-box;
  width: 20px;
  height: 20px;
  background-color: #fff;
  border: solid .3px #333;
  top: 20px;
  left: 20px;
}